Capsular sialic acid of Streptococcus suis serotype 2 binds to swine influenza virus and enhances bacterial interactions with virus-infected tracheal epithelial cells

Streptococcus suis serotype 2 is an important swine bacterial pathogen, and it is also an emerging zoonotic agent. It is unknown how S. suis virulent strains, which are usually found in low quantities in pig tonsils, manage to cross the first host defense lines to initiate systemic disease. Influenza virus produces a contagious infection in pigs which is frequently complicated by bacterial coinfections, leading to significant economic impacts. In this study, the effect of a preceding swine influenza H1N1 virus (swH1N1) infection of swine tracheal epithelial cells (NTPr) on the ability of S. suis serotype 2 to adhere to, invade, and activate these cells was evaluated. Cells preinfected with swH1N1 showed bacterial adhesion and invasion levels that were increased more than 100-fold compared to those of normal cells. Inhibition studies confirmed that the capsular sialic acid moiety is responsible for the binding to virus-infected cell surfaces. Also, preincubation of S. suis with swH1N1 significantly increased bacterial adhesion to/invasion of epithelial cells, suggesting that S. suis also uses swH1N1 as a vehicle to invade epithelial cells when the two infections occur simultaneously. Influenza virus infection may facilitate the transient passage of S. suis at the respiratory tract to reach the bloodstream and cause bacteremia and septicemia. S. suis may also increase the local inflammation at the respiratory tract during influenza infection, as suggested by an exacerbated expression of proinflammatory mediators in coinfected cells. These results give new insight into the complex interactions between influenza virus and S. suis in a coinfection model

Perfil de resistencia antimicrobiana de Staphylococcus pseudintermedius resistentes a meticilina, aislados de dermatitis canina : Resultados preliminares

Staphylococcus pseudintermediuses es el patógeno oportunista más común en perros, relacionado frecuentemente a piodermias. Los aislamientos S. pseudintermedius resistentes a metilicina (SPRM) están asociados con portación del gen mecA, que codifica una proteína (PBP2a) con baja afinidad por los antibióticos beta- lactámicos. La incidencia de SPRM ha aumentado significativamente en todo el mundo y se ha convertido en un problema importante debido a la resistencia a múltiples fármacos (MDR), además del riesgo potencial de transmisión zoonótica. El objetivo de este estudio fue determinar los perfiles de sensibilidad antimicrobiana y genes de resistencia en SPMR aislados de muestras clínicas de piel de caninos en la región de Área Metropolitana de Buenos Aires (AMBA). Se analizó un total de n=52 estafilococos coagulasa-positivos (ECP) aislados de muestras clínicas de dermatitis canina, obtenidos de un laboratorio dediagnóstico veterinario de la provincia Buenos Aires. Los aislamientos se identificaron por pruebas bioquímicas convencionales y pruebas moleculares mediante la determinación del gen nuc.Trabajo publicado en Cagliada, Maria del Pilar Lilia y Galosi, Cecilia Mónica (comps.). I Congreso de Microbiología Veterinaria. Libro de resúmenes. La Plata: Facultad de Ciencias Veterinarias, 2021.Facultad de Ciencias Veterinaria

Whole-genome sequencing and phylogenetic analysis capture the emergence of a multi-drug resistant Salmonella enterica serovar Infantis clone from diagnostic animal samples in the United States

IntroductionSalmonella enterica is a major cause of foodborne illness in the United States. A multi-drug resistant (MDR) emergent Salmonella Infantis (ESI) with a megaplasmid (pESI) was first identified in Israel and Italy and subsequently reported worldwide. The ESI clone carrying an extended spectrum β-lactamase blaCTX-M-65 on a pESI-like plasmid and a mutation in the gyrA gene has recently been found in the United States in poultry meat.MethodsWe analyzed the phenotypic and genotypic antimicrobial resistance, genomics and phylogeny of 200 S. infantis isolates from animal diagnostic samples.ResultsOf these, 33.5% were resistant to at least one antimicrobial and 19.5% were multi-drug resistant (MDR). Eleven isolates from different animal sources were phenotypically and genetically similar to the ESI clone. These isolates had a D87Y mutation in the gyrA gene conferring reduced susceptibility to ciprofloxacin and harbored a combination of 6–10 resistance genes: blaCTX-M-65, aac(3)-IVa, aadA1, aph(4)-Ia, aph(3′)-Ia, floR, sul1, dfrA14, tetA, and fosA. These 11 isolates carried class I and class II integrons and three virulence genes: sinH, involved in adhesion and invasion, ybtQ and ybtP, associated with iron transport. These isolates were also closely related to each other (separated by 7 to 27 SNPs) and phylogenetically related to the ESI clone recently found in the U.S.DiscussionThis dataset captured the emergence of the MDR ESI clone in multiple animal species and the first report of a pESI-like plasmid in isolates from horses in the U.S

First isolation of a methicillin-resistant Staphylococcus aureus from bovine mastitis in Argentina

This research communication describes the first isolation of a methicillin-resistant Staphylococcus aureus (MRSA) from cow´s mastitic milk in Argentina. Bovine mastitis causes important economic losses in the dairy industry and the most commonly isolated bacteria from bovine mastitis are staphylococci. The mecA gene present in MRSA bacteria confers resistance to almost all β-lactam antibiotics, the most frequent drugs used in bovine mastitis therapy.Fil: Srednik, Mariela Elizabeth. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Área de Microbiología Veterinaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Crespi, Elisa Silvia. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Área de Microbiología Veterinaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Testorelli, María Florencia. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Área de Microbiología Veterinaria; ArgentinaFil: Puigdevall, Tomas Juan. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Área de Microbiología Veterinaria; ArgentinaFil: Pereyra, Ana María. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Área de Microbiología Veterinaria; ArgentinaFil: Rumi, María Valeria. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Área de Microbiología Veterinaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Caggiano, Nicolás. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: Gulone, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Mollerach, Marta Eugenia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Gentilini, Elida Raquel. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Área de Microbiología Veterinaria; Argentin

Mastitis bovina : estudios moleculares, fenotípicos y biológicos de estafilococos coagulasa negativa

Bovine mastitis is considered one of the main causes of economic losses in dairy cows. Although it is caused by several etiological agents, in recent years\nthe prevalence of coagulase-negative staphylococci (CNS) has increased worldwide, being considered an emerging pathogen. Recent studies show that microorganisms among the CNS group have the ability to form biofilm and\nbecause of that, they could persist in the mammary gland. It is important to\nhighlight the implications to public health, since CNS are reservoirs of resistance genes. The objective of this study was to evaluate the antimicrobial susceptibility and the presence of resistance genes to antimicrobial agents\ncommonly used in bovine mastitis therapeutics. Furthermore, to evaluate biofilm formation, enzymatic treatments of biofilms formed by CNS, and the presence of virulence genes in CNS isolates from bovine mastitis from different dairy\nherds in Argentina. 138 CNS isolates were identified at the species level by\nrestriction fragment length polymorphism (RFLP) analysis of the gap gene. The most prevalent CNS species were staphylococcus chromogenes (n=59,\n42.8%), Staphylococcus epidermidis (n=19, 13.8%) and Staphylococcus\ndevriesei (n=12, 8.7%).\nGenes encoding resistance to ?-lactams (n=26; 28.8%) were detected among\nthe isolates: blaZ (n=28, 20.3%), mecA (n=4, 2.9%) and mecC (n=1, 0.7%).\nResistance to macrolides and lincosamides (n=14, 10.1%) was attributable \nermC (n=9, 6.5), ermB (n=6, 4.3), mphC (n=5, 6%) and mrsA (n=3, 2.2%),\nalone or in a combination of those genes.\n\nThe majority (93.5%) of isolates was able to form biofilms. Among the biofilm-\npositive isolates, 37.2%, 11.6% and 51.2% were strong, moderate and weak\nbiofilm formers, respectively. The ability to form biofilms varied among CNS\nspecies. S. haemolyticus and S. devriesei isolates formed significantly more\nbiofilms than other species. Enzymatic treatment results suggest that proteins\nand eDNA play a larger role in the structural integrity of CNS biofilms. icaA\n(n=9, 6.5%), bap (n=5, 3.6%) and aap (n=5, 3.6%) were detected in a few\nisolates, while atlE (n=38, 27.5%), embP (n=35, 25,4%) and fbe (n=20, 14.4%) were detected in a considerable number of CNS. The eno gene (n=122, 88.4%) was present in the majority of isolates.\nThe results obtained show differences in the ability of biofilm formation among\nCNS species and there are intra-species variations. Although antimicrobial\nresistance to common antibiotics is low, it is important to highlight the presence of methicillin-resistant CNS carrying the mecA/C genes, important for the public health implications, since CNS are reservoirs of resistance genes. In this study,\nwe identified CNS species involved in mastitis and provide information about\npathogenicity and antimicrobial resistance, which is essential to design efficient strategies to control mastitis caused by CNS.\nFuture studies should be carried out to examine the association of biofilm\nformation with treatment failure and the occurrence of persistent intramammary\ninfections by different CNS species in cattle.Fil: Srednik, Mariela E. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Buenos Aires, ArgentinaLa mastitis bovina es considerada una de las principales causas de pérdidas económicas en el sector lechero. Si bien es causada por numerosos agentes microbianos, en los últimos años la frecuencia de aislamientos de estafilococos coagulasa-negativos (ECN) se ha incrementado undialmente,\nconsiderándose un patógeno emergente. Estudios recientes demuestran que\ndeterminadas especies que integran el grupo de los ECN presentan la habilidad\npara formar biofilm y así podrían persistir en la glándula mamaria. Además, es importante destacar las implicancias en salud pública, por ser los ECN\nreservorios de genes de resistencia a antimicrobianos y por la posibilidad de transferencia de resistencia. El objetivo de este estudio fue identificar las especies de ECN, determinar la susceptibilidad y portación de genes de\nresistencia a antibióticos de uso habitual en la terapéutica antimastítica.\nAdemás, detectar formación de biofilm, su dispersión enzimática, y la portación\nde genes de virulencia, en especies de ECN aislados de mastitis bovina de\ndiferentes tambos de Argentina. Por el análisis del polimorfismo en la longitud\nde fragmentos de restricción (RFLP) del gen gap, se identificaron 138\naislamientos a nivel de especie. Los resultados arrojaron que, las especies de ECN más prevalentes resultaron: Staphylococcus chromogenes (n=59, 42,8%),Staphylococcus epidermidis (n=19, 13,8%) y Staphylococcus devriesei (n=12,\n8,7%).\n?Mastitis Bovina: Estudios Moleculares y Fenotípicos de Estafilococos Coagulasa Negativos? En distintas especies fueron detectados genes responsables de la resistencia a ?-lactámicos (n=26; 18,8%), como el gen blaZ (n=28; 20,3%), mecA (n=4; 2,9%) y mecC (n=1; 0,7%). Con respecto a la resistencia a macrólidos y\nlincosamidas (n=14; 10,1%) fue atribuible a los genes ermC (n=9; 6,5%), ermB\n(n=6; 4,3%), mphC (n=5; 3,6%) y msrA (n=3; 2,2%), estando solos o en\ncombinaciones.\nLa mayoría (93,5%) de los aislamientos analizados presentaron habilidad para\nformar biofilm. De este total, el 37,2%, 11,6% y 51,2% resultaron fuertes,\nmoderados y débiles formadores de biofilm, respectivamente. La capacidad de formación de biofilm mostró variaciones en las distintas especies.\nStaphylococcus haemolyticus y S. devriesei resultaron los mayores productores de biofilm. Los resultados de los tratamientos enzimáticos sugieren que las\nproteínas y el ADN extracelular desempeñarían un papel más importante en la matriz del biofilm de los ECN. Los genes asociados a biofilm se detectaron sólo en algunos aislamientos,\nsiendo para icaA (n=9; 6,5%), bap (n=5; 3,6%) y aap (n=5; 3,5%), mientras que los genes atlE (n=38; 27,5%), embP (n=35; 25,4%) y fbe (n=20; 14,4%) se detectaron en mayor cantidad de aislamientos, y el gen eno (n=122; 88,4%) en casi todas las especies. Los resultados obtenidos demuestran que la\nresistencia de los ECN frente a los antibióticos de uso habitual en las mastitis,\nen general es baja comparada con otros países. Es importante que se encontraron aislamientos meticilino-resistentes portadores de los genes\nmecA/C, por las implicancias que esto tiene en salud pública, al ser los ECN reservorios de genes de resistencia. Además, se observó que los ECN son\n?Mastitis Bovina: Estudios Moleculares y Fenotípicos de Estafilococos Coagulasa Negativos? productores de biofilm y, que existen diferencias en la capacidad de formación en las distintas especies y además variaciones intraespecies.\nEste estudio aporta información sobre las distintas especies de ECN\ninvolucradas en mastitis bovina, factores de patogenicidad y datos sobre\nfrecuencia, emergencia y mecanismos de resistencia antimicrobiana,\npermitiendo al profesional diseñar estrategias eficaces para el control de las\nmastitis bovina.\nEstudios futuros deberían llevarse a cabo para examinar la asociación de la\nformación de biofilm con el fracaso de los tratamientos y la aparición de infecciones intramamarias persistentes por las distintas especies de ECN en bovino

Molecular identification of coagulase-negative staphylococci isolated from bovine mastitis and detection of beta-lactam resistance

Introduction: Bovine mastitis is a frequent cause of economic loss in dairy herds. Coagulase-negative staphylococci (CoNS) are increasing in importance as cause of bovine intramammary infection throughout the world in recent years. CoNS have been isolated from milk samples collected from cows with clinical and subclinical mastitis in several countries. Identification of mastitis pathogens is important when selecting appropriate antimicrobial therapy. Methodology: A total of 93 strains of Staphylococcus spp isolated from bovine mastitis in Argentina between 2010 and 2013 were identified by PCR-restriction fragment length polymorphism (PCR-RFLP) using the gap gene and were tested for the presence of blaZ and mecA genes by PCR and for the susceptibility to penicillin and cefoxitin by disk diffusion. Results: The most common CoNS species was S. chromogenes 46.2% (43/93), followed by S. devriesei 11.8% (11/93) and S. haemolyticus 9.7% (9/93). The blaZ gene was detected in 19 (20.4%), but only 16 (17.2%) isolates were resistant to penicillin; the mecA was detected in 6 (6.5%) isolates but only 4 (4.3) were resistant to cefoxitin. The 6 mecA-positive isolates showed oxacillin MICs = 0.5 µg/ml. Discussion: CoNS are important minor mastitis pathogens and can be the cause of substantial economic losses. The presence of methicillin resistant isolates emphasizes the importance of identification of CoNS when an intramammary infection is present because of the potential risk of lateral transfer of resistant genes among staphylococcal species.Fil: Srednik, Mariela Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; ArgentinaFil: Grieben, Mario A.. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: Bentancor, Adriana Beatriz. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: Gentilini, Elida Raquel. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; Argentin

Antibiotic susceptibility of staphylococci isolated from bovine mastitis milk samples

La mastitis es una enfermedad que afecta la salud de los bovinos y produce grandes pérdidas económicas. Los microorganismos de mayor prevalencia en la Argentina pertenecen al género Staphylococcus, siendo el patógeno principal S. aureus, aunque los estafilococos coagulasa negativos (ECN) han adquirido importancia por la capacidad de expresar factores de virulencia y resistencia a antimicrobianos. El objetivo de este estudio fue determinar in vitro la concentración inhibitoria mínima (CIM) de betalactámicos y macrólidos-lincosamidas frente a estafilococos aislados de leche de vacas con mastitis. Se estudiaron (n=162) aislamientos, (n=65) S. aureus y (n=97) ECN. El 33,8% (22/65) de S. aureus presentó resistencia a penicilina, siendo la CIM90: 0,5 µg/ml, el 7,7% (5/65) a eritromicina con una CIM90: 1 µg/ml y el 6,1% (4/65) a clindamicina con una CIM90: 0,1 µg/ml. El 30,9% (30/97) de los ECN fueron resistentes a penicilina siendo la CIM90: 0,25 µg/ml, el 7,2% (7/97) a eritromicina con una CIM90: 0,5 µg/ml, el 4,1% (4/97) a clindamicina con una CIM90: 0,12 µg/ml y el 3,1% (3/97) a oxacilina siendo la CIM90: 0,38 µg/ml. No se observó meticilino resistencia en S. aureus. El diagnóstico bacteriológico y la determinación de susceptibilidad junto con el manejo adecuado del rodeo lechero, son fundamentales para el control de la enfermedad.Palabras clave: (concentración inhibitoria mínima), (mastitis bovina), (resistencia), (Staphylococcus spp)Mastitis is a disease that affects the health of cattle and causes great economic losses. The most 24 prevalent microorganisms in Argentina belong to the genus Staphylococcus, being the main pathogen 25 S. aureus, though coagulase-negative Staphylococci (CNS) have gained importance for the ability to 26 express virulence factors and antimicrobial resistance. The aim of this study was to determine 27 phenotypically in vitro minimum inhibitory concentrations of betalactams and macrolide-lincosamide 28 against staphylococci isolated from mastitic milk. We studied (n=162) isolates, (n=65) S. aureus and 29 (n=97) CNS. The 33,8% (22/65) of S. aureus presented resistance to penicillin, being the MIC90: 0,5 30 µg/ml, the 7,7% (5/65) to erythromycin with a MIC90: 1 µg/ml and 6,1% (4/65) to clindamycin with a 31 MIC90: 0,1 µg/ml. The 30,9% (30/97) of CNS were resistant to penicillin being the MIC90: 0,25 µg/ml, 32 the 7,2% (7/97) to erythromycin with a MIC90: 0,5 µg/ml, the 4,2% (4/97) to clindamycin with a 33 MIC90: 0,12 µg/ml and 3,1% (3/97) to oxacillin being the MIC90: 0,38 µg/ml. Methicillin-resistance 34 was not observed in S. aureus. Bacteriological diagnosis and susceptibility determination with proper 35 management of dairy herd are essential for disease control.Fil: Srednik, Mariela Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: Abate, S.. No especifica;Fil: Gentilini, Elida Raquel. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; Argentin

Antibiotic Resistance/Susceptibility Profiles of Staphylococcus equorum Strains from Cheese, and Genome Analysis for Antibiotic Resistance Genes

In food, bacteria carrying antibiotic resistance genes could play a prominent role in the spread of resistance. Staphylococcus equorum populations can become large in a number of fermented foods, yet the antibiotic resistance properties of this species have been little studied. In this work, the resistance/susceptibility (R/S) profile of S. equorum strains (n = 30) from cheese to 16 antibiotics was determined by broth microdilution. The minimum inhibitory concentration (MIC) for all antibiotics was low in most strains, although higher MICs compatible with acquired genes were also noted. Genome analysis of 13 strains showed the S. equorum resistome to be composed of intrinsic mechanisms, acquired mutations, and acquired genes. As such, a plasmidic cat gene providing resistance to chloramphenicol was found in one strain; this was able to provide resistance to Staphylococcus aureus after electroporation. An msr(A) polymorphic gene was identified in five strains. The Mrs(A) variants were associated with variable resistance to erythromycin. However, the genetic data did not always correlate with the phenotype. As such, all strains harbored a polymorphic fosB/fosD gene, although only one acquired copy was associated with strong resistance to fosfomycin. Similarly, a plasmid-associated blaR1-blaZI operon encoding a penicillinase system was identified in five ampicillin- and penicillin G-susceptible strains. Identified genes not associated with phenotypic resistance further included mph(C) in two strains and norA in all strains. The antibiotic R/S status and gene content of S. equorum strains intended to be employed in food systems should be carefully determined

Characterisation of Staphylococcus aureus strains isolated from mastitis bovine milk in Argentina

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